Encoders are used to measure angular or linear motion. A common use of encoders is for computer numeric control (CNC) machines. In one type of encoder, e.g., a rotary encoder, an encoder disk is rotatable with a shaft of, e.g., a motor, relative to detector electronics that are mounted in a housing of the encoder. In such rotary encoders, it is generally necessary to radially align the encoder disk relative to the shaft so that the rotation axis of the shaft is coaxial to the center of the encoder disk to thereby radially align the rotation axis of the encoder disk relative to the detector electronics. It may also be necessary to gap the encoder disk relative to the detector electronics. That is, it may be necessary to axially align the encoder disk relative to the detector electronics. Such alignment may facilitate installation of the encoder onto the shaft prior to securing the encoder disk to the shaft.
Further, prior to installation onto the shaft, the encoder disk and/or the interior components of the encoder may be damaged due to movement of the encoder disk relative to the housing and associated contact and/or impact between components.
Examples of gapping and centering devices are described, for example, in U.S. Pat. No. 5,057,684, U.S. Pat. No. 5,708,496, U.S. Pat. No. 6,714,292, European Published Patent Application No. 0 557 564, U.S. Pat. No. 6,452,160, U.S. Pat. No. 4,794,250, U.S. Pat. No. 4,942,295, and U.S. Pat. No. 4,512,184. Conventional gapping and centering devices typically require at least two separate parts in addition to the other parts of the encoder device, e.g., the housing and the cover. Many of these devices, for example, those described in U.S. Pat. No. 6,714,292, utilize a slide mechanism.
Minimizing the number of parts may be beneficial to reduce manufacturing costs and to reduce the potential for misassembly.